The end of Christiania has been predicted for some time. Plonked on a potentially lucrative chunk of real estate south of the centre of Copenhagen, it has existed as a self-proclaimed "freetown" since a group of squatters claimed the ex-military barracks in 1971. Its relaxed approach to soft drugs - the main street is called Pusher Street, where until recently hash was sold openly from stalls - has inevitably drawn the attention of the local authorities, whose cat-and-mouse relationship with the residents has become more heavy-handed by the year. This January, the government announced its intention to install privately owned condominiums for 400 new residents.

I visited the community last year, and found the whole thing rather depressing. The aesthetic is still unique - mural-lined dirt tracks, inventively adapted housing - but the impending doom is palpable. Vendors selling Christiania T-shirts and hash-smoking paraphernalia look tired, "the dream is over" written on their faces.

Thank goodness, then, for Nørrebro. Having developed in the mid-19th century as a working-class district, the 70s and 80s saw a wave of Muslim immigrants move into the area, drawn by the cheap rent. For exactly the same reason, Copenhagen's gifted-but-broke literati and arty set have been moving in ever since. The result is an exciting, occasionally angry, increasingly trendy alternative to Christiania; without the relaxed drugs laws, but also without the tourists.

It may never have proclaimed Christiania-style independence, but Nørrebro is far from teacher's pet. Following the attempted deportation of second-generation immigrants in the late 90s, Nørrebro became the focal point of civil unrest in the country, a scene repeated following the publication of the Muhammad cartoons last year. Nørrebro's rebellious streak extends to its businesses - retro junk shops, specialist vinyl stores and grungy coffee shops pepper the streets - yet in spite (and probably because) of its quirks, the area is a favourite haunt for Copenhagen's middle-class teenagers, media types and upwardly mobile.

Of all Nørrebro's quirks, perhaps the most indelible is "Rub-a-Dub Sundays". Full name: "Rub-a-Dub Sundays - We Fuck up Your Mondays". For most of the week, Stengade 30 is a rock club, more suited to rebels than rastas, but on Sunday nights the Rub-a-Dub boys transform the place into surely Scandinavia's finest dub reggae and ragga night (how many can there be?) While Danish white boys and dub reggae might seem like odd bedfellows, in Nørrebro it manages to work, with Rub-a-Dub always attracting the requisite amount of local rastas to give the whole thing a bit of credibility.

Brick Lane, London For centuries, an immigrant area - Huguenot, Jewish, then Bangladeshi - now colonised by indy types, radio-production companies etc. Famous for nightlife (93 Feet East and the Big Chill Bar are current favourites) and the best curries and bagels in London.

Lavapies, Madrid Cafe-lined streets thick with shisha smoke and punk riffs. Home to the Artepolis (espacioartepolis.com), a busy underground community art centre, and a raging bar and nightlife scene.

Gronland, Oslo The Pakistani immigrants have recently been joined by students, and "Little Karachi" is now awash with cafe culture and trendy bars.

Kreuzberg, Berlin Home to the city's largest Turkish and Kurdish community. Also home to a multitude of restaurants, oddly themed bars (the Wild at Heart bar on Wiener Strasse offers "hardcore Hawaiian"), and the world's only Ramones Museum (ramonesmuseum.com).